PROJECT SUMMARY This proposal aims to develop and pilot test a theoretically-grounded, behavioral intervention to promote the development of a therapeutic alliance between oncologists and Latino advanced cancer patients. This intervention will be grounded in the theoretical model of the TA and a conceptual model of the TA in Latino cancer patients that we will develop through the proposed formative research. Based on data from the literature and our preliminary studies, this intervention will seek to improve oncologist TA by promoting trust, empathy, shared decision-making, and patient-centered communication. The intervention framework will be based on Self Determination Theory (SDT), which posits that behaviour change (improvement in TA) is more likely when conditions of autonomy, competence, and relatedness are met. First, mixed methods will be used to create a conceptual model of the TA between oncologists and Latino cancer patients to determine targets for the intervention (Fig 1). Aim1a will leverage data from an ongoing funded multi-site, prospective observational R01 on medical/religious/cultural beliefs, TA, and EOL care outcomes (n>270). For Aim 1b, we will conduct in-depth interviews and focus groups with oncologists (n=9) and Latino cancer patients (n=35) in order to gain a more nuanced understanding of the TA and refine our conceptual model. Once the intervention has been created, we will then refine the intervention using stakeholder (Aim 1b participants) feedback regarding its feasibility and acceptability. For Aim 3, an independent set of 8 oncologists and 50 patients will be studied, half (n=4 oncologists, 25 patients) will be randomized to training in the TA intervention, and the other half (n=4, 25) will be randomized in to usual care. We will examine feasibility (rate of intervention completion), acceptability (oncologists? and patients? satisfaction), and efficacy of the TA intervention for improving the TA between oncologists and Latino cancer patients, as measured by patient THC scores as the primary outcome. Secondary outcomes will include engagement in ACP and EOL care. Dr. Tergas?s long-term career goal is to establish a leading, independent program of research focused on the reduction of disparities in EOL care by implementing and disseminating effective, empirically-supported interventions for use in clinical practice. As a foundation for her independent research program, her short-term career goal is to develop an implementable, evidence-based behavioral intervention for improving therapeutic alliance between oncologists and Latino cancer patients. This K08 award application represents the cornerstone of her strategy to achieve my short- term goal and consists of cohesive and complementary research aims and training objectives. Specifically, in order to achieve her career goals, she needs training in intervention development and implementation science, as well as continued training and mentorship in EOL care disparities. Conducting the research detailed in my research aims will help me achieve this training and experience, as well as provide preliminary data for a future R01-level grant application.